let’s call it what it is. your child’s tiny attention span and subsequent tantrums are due to your policies of instant gratification and no consequences. your child does not have a disorder. your child just does not have manners and does not understand boundaries. you should be much more than embarrassed, you should be terrified for your child’s future.
disclaimer: I respect ADHD as a proven disorder, which is why I do not appreciate the misuse of the syndrome in wrongly diagnosing demonic, spoilt children of the frickin first world.